Colorectal cancer can begin unnoticed. By the time you develop symptoms, it may have grown and spread, making it harder to treat.

While colorectal cancer was once most often diagnosed among those ages 50 and older, now younger people also need to be on the alert.

The American Cancer Society reports that the number of younger adults diagnosed with colon cancer in their 20s and 30s is increasing. On the other hand, the diagnostic rates for those in their 50s or older is experiencing a slight decline.

According to Dr. Damaris Gautier, a medical director for Blue Cross and Blue Shield, doctors don’t yet see a clear reason for the increasing colon cancer rates in younger people. “If we had to make a guess, the increase could be attributed to genetic factors, but there are also environmental factors, such as being exposed to harmful substances or triggers that cause the body to change,” Dr. Gautier said.

“We also know that obesity as well as diets that are low in fiber and water intake can factor into an increased likelihood for developing colon cancer,” she said.

When cancer is caught early, there are often treatment options. The U.S. Preventive Services Task Force says most adults at average risk for the disease should start screening at age 50. But it is important to take action earlier if you are at high risk for colon cancer. You may need to begin testing at a younger age.

Who’s at High Risk?

Talk to your doctor if you have these high-risk factors:

A personal history of colorectal cancer or precancerous polyps

A family history of the disease

Chronic inflammatory bowel disease, including ulcerative colitis or Crohn’s disease, a condition that causes the colon to be chronically inflamed

What Are the Screening Options?

While screening can help spot this cancer early, many people still avoid this potentially lifesaving tool.

Colonoscopy is the most common screening tool. A doctor uses a colonoscope — a flexible, lighted tube with an attached camera — to look at the entire rectum and colon for signs of cancer. The doctor can even remove precancerous growths called polyps during the procedure.

Unfortunately, some people may avoid a colonoscopy because they are nervous about it. In fact, they may pass up colorectal cancer screening altogether.

Dr. Gautier says there’s no reason to be afraid of the procedure. “The worst thing is the prep before even going in for the test,” she said.

The test itself is so painless that some patients don’t even realize when it’s over and done. “Many patients…wake up and ask, ‘When are you are taking me for the test?’ The hardest part of a colonoscopy is not the test, there is nothing to be concerned or scared about.”

Other screening options are available, based on your doctor’s recommendation. However, a colonoscopy is more comprehensive since it offers the opportunity to immediately remove a polyp if necessary.

Other screening options may include:

A fecal occult blood test: A lab scans a stool sample for blood, a possible sign of cancer.

Sigmoidoscopy: This procedure is similar to a colonoscopy, but it looks only at the rectum and the lower colon.

Barium enema: A series of X-rays highlight any problems in the colon and rectum.

Virtual colonoscopy: A CT scan supplies detailed images of the colon.

What Are the Symptoms?

Early colon cancer may not have any symptoms, which is why screening is so important. Warning signs include:

Anemia, which causes symptoms such as weakness, excessive fatigue and sometimes shortness of breath.

Bleeding from the rectum.

Blood in the stool or in the toilet after having a bowel movement.

Dark or black stools.

A change in bowel habits or the shape of the stool not caused by a change in diet.

An urge to have a bowel movement when the bowel is empty.

Can You Prevent Colorectal Cancer?

These healthy lifestyle tips may help to protect you from colon cancer:

Eat a diet that’s high in fruits, vegetables and fiber.

Avoid eating red, grilled meats and processed meats.

Avoid smoking, heavy use of alcohol and sedentary lifestyles.

Exercise.

Keep weight in check.

Play it smart.

Colorectal cancer can cross all age boundaries. If you notice anything that could be a symptom, including any of those listed above, play it smart and talk to your health care provider. Like most illnesses, an early diagnosis gives you the best chance to make a successful recovery.

Family matters.

One of the best ways to assess your risk for certain diseases is to review your family’s health history. Do you have a family event like a reunion or a potluck meal planned? Take the opportunity to talk about the chronic conditions that may run in your family.

Look beyond your immediate family and find out about grandparents, aunts, uncles and cousins. If your relatives are uncomfortable talking in a group, use one-on-one time.

Develop a checklist of what you find out and share it with your doctor. This information can guide your decisions about early screenings for issues such as heart disease, diabetes and some cancers.

Want to ditch the notepad? The U.S. Surgeon General provides My Family Health Portrait, an online tool to help collect information. Or you can download this handy checklist from the March of Dimes.

Colorectal screenings are covered at no cost to you.

A colorectal screening is one of the preventive services available to you at no cost.* Talk to your doctor to see if you should be screened.

Learn more about cancer risk and prevention.

Visit the Cancer section on this website for information about cancer risk, screening options and prevention.

*Preventive services at no cost applies only to members enrolled in non-grandfathered health plans. You may have to pay all or part of the cost of preventive care if your health plan is grandfathered. To find out if your plan is grandfathered or non-grandfathered, call the customer service number on your member ID card.